Principles of Consolidation - Summary of Unconsolidated Variable Interest Entity's Sponsored by Redwood (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
On-balance sheet assets, at fair value:
Subordinate securities, classified as AFS	$ 185,198	$ 206,792
Servicing asset, fair value	265,949	310,953
Variable Interest Entity, Not Primary Beneficiary
On-balance sheet assets, at fair value:
Maximum loss exposure	142,141	152,206
Assets transferred:
Principal balance of loans outstanding	4,491,763	4,959,234
Principal balance of loans 30+ days delinquent	27,286	30,594
Interest-only, senior and subordinate securities, classified as trading | Variable Interest Entity, Not Primary Beneficiary
On-balance sheet assets, at fair value:
Interest-only, senior and subordinate securities, classified as trading	24,246	18,214
Subordinate securities, classified as AFS | Variable Interest Entity, Not Primary Beneficiary
On-balance sheet assets, at fair value:
Subordinate securities, classified as AFS	108,768	127,542
Mortgage servicing rights
On-balance sheet assets, at fair value:
Servicing asset, fair value	19,739	12,438
Mortgage servicing rights | Variable Interest Entity, Not Primary Beneficiary
On-balance sheet assets, at fair value:
Servicing asset, fair value	$ 9,127	$ 6,450